Apparatus for fine pulverization of dry leaves and garden debris

ABSTRACT

An apparatus for finely pulverizing lawn debris has a central drive shaft with a clutch driven by a gasoline or electrical power source. Lawn debris is drawn into a suction chamber by a fan impeller blade mounted on the central drive shaft. The fan impeller blade initiates pulverization of the debris. A grinding blade with a plurality of blade elements is mounted on the central drive shaft below the fan impeller blade and effects additional pulverization of the debris. A clutch is mounted next on the drive shaft followed by a distributing plate with a plurality of inclined apertures for dispensing a high velocity stream of the pulverized debris uniformly over a lawn from the rotating distributing plate. When the clutch is disengaged the distributing plate rotation is stopped and the finely pulverized garden debris is collected in a side collection chamber and is periodically emptied through a bottom discharge gate.

This is a Continuation-In-Part of application Ser. No. 10/340,456, filedJan. 10, 2003, now U.S. Pat. No. 6,701,698 the disclosure of which ishereby incorporated in its entirety by reference thereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a leaf grinding apparatus; and moreparticularly, to a portable composter that automatically picks-up lawndebris, pulverizes it into a fine compostable powder, and either i)collects it in a side collection chamber so that it may be suitablydischarged at a user selected location at a later time or ii)automatically distributes it uniformly over the lawn to enhance theappearance thereof and improve soil fertility.

2. Description of the Prior Art

Those responsible for maintenance of the grounds of homes and commercialbuildings have long struggled to devise a method and means foraddressing the seemingly endless accumulation of garden refuse, such asleaves, sticks and debris on the outdoor surfaces of the property,including lawns, gardens, patios, walkways and the like. Numerousteachings relate to machinery adapted to pick up leaves and debris fromoutside surfaces, shred them into smaller particles, and re-distributethe pulverized product into the soil. A wide variety of mechanisms feedgarden refuse into such machinery, wherein it is reduced to smallparticles, bagged or otherwise disposed of.

U.S. Pat. No. 2,647,694 to Williams et al. discloses a leaf grinderapparatus comprising a vertical frame having a triangular base. Anelectric motor drives a pair of pulleys which turn a screw leaf feed andcutting blade mechanism. Leaves fed into a hopper are pushed against thescrew feed, which delivers the leaves into a stationary-keyed disc. Aplurality of arc-shaped apertures on the disc transport the leaves intocutting blades, which are driven by the electric motor. Leaves are fedmanually into the hopper. An arc shaped leaf pusher feeds the leavesinto the screw mechanism. The leaves pass once through a single cuttingblade, which attempts to cut and shred them. Due to the manual feed andsingle cutting blade, particle size reduction of the leaves and debrisexiting the apparatus is oftentimes insufficient and non-uniform,causing uneven distribution thereof.

U.S. Pat. No. 2,658,318 to Miller et al. discloses a suction leaf pickupwherein a single cutting centrifugal impeller blade propels the shreddedleaves against a perforated cylinder. The perforated cylinder isdisposed in the path of the shredded leaves and generally perpendicularto the shaft, which rotates the centrifugal impeller. Due to theperforations only those pulverized leaves which are small enough in sizeto be discharged exit the device. The exiting leaves move generallysideways in a direction perpendicular to the motion of the device. Adischarge orifice through which the leaves exit is located high abovethe device so that it projects the pulverized leaves over the lawn orsoil. In as much as the single cutting blade must also function as asuction device, particle size reduction of the leaves and debris exitingthe apparatus is inefficient and non-uniform. Perforations in thecylinder become clogged by large leaf fragments. This problem is notavoided by the use of an elevated, low velocity discharge. Distributionof the pulverized leaves and debris is not accomplished in an efficient,reliable manner. The shredded leaves are too large and non-uniform forproper fertilization of lawn and garden soil.

U.S. Pat. No. 2,706,372 to Blydenburgh discloses a leaf grinder having adisk type blade containing additional leaf beating members. An expandedmetal cylinder 44 is attached to the casting of the device. The beatingmembers crush the leaves against the roughened portions or mesh producedby the sharp edged multiple edges formed in the expanded metal. Afterbeing crushed the leaf particles pass out through the metal mesh.Pulverizing of the dry leaves is solely accomplished by the leaf-beatingand physical crushing against a sharp expanded metal rough surfaceforming a metal mesh in the sidewall casing through which the leavespass. Leaf particles that are too large to pass through the metal meshbecome loosely attached thereto. The mesh becomes clogged, preventingproper discharge of ground leaf particles. Particle size reduction ofleaves and debris is restricted and distribution of shredded gardenrefuse is non-uniform.

U.S. Pat. 2,984,961 to Judkins discloses a lawn cleaner andsnow-clearing device. The device comprises a frame having a closed hood,a power source, a power supply support, a rotary drive shaft with adirectly coupled cutting and suction blade and an orthogonal gear boxwith a blower fan blade. Grass is cut using a cutting and suction blade.The grass clipping and other lawn materials are drawn through the upperportion of the hood by the action of the suction blade. Lawn material isthen drawn into the blower shaft by the blower fan. A blower shaftcasing with perforations retains the lawn material in the blower shaftuntil the lawn material has been sufficiently pulverized by the blowerfan. The pulverized lawn leaves exit the lawn cleaner through a bloweroutlet at the end of the blower shaft. In the Judkins device, leaves aredrawn into the hood of the lawn cleaner by the grass-cutting blade.Pulverizing is accomplished by the interaction between a slowly rotatingblower fan and a plurality of casing perforations, which retain andrecycle larger uncut pieces of leaves. The blower outlet tends to becomeclogged by large fragments of uncut leaves. Garden refuse is dischargedat low velocity from an elevated location, causing non-uniformdistribution of shredded material over the lawn or soil.

U.S. Pat. No. 3,058,284 to Anderson discloses a lawn debris choppercomprising a mobile frame. Power is provided by a lawn mower gasolineengine connected to a cutting blade by direct drive. A drive belt isconnected to a centrifugal blower and a chopper. The centrifugal blowerreceives an air stream carrying lawn material through a duct and passesit into a worm type feeding mechanism. Lawn material is extruded to astationary perforated blade and a rotating cutting blade. Discharge ofshredded lawn material is effected from a high location in a lateraldirection generally perpendicular to the direction of motion of the lawndebris chopper. Due to the reduced speed of the cutting blade, cuttingaction is inefficient. Garden refuse is propelled at an insufficientspeed for uniform distribution. Stationary blade perforations arrangethe shredded debris into a fine stream, but do not cut or chop thedebris. Cutting is accomplished solely by the cutting blade, therebylimiting particle size reduction. The outlet port becomes clogged byoversize lawn debris from the suction blade. Distributed particles areoften too large for proper lawn fertilization.

U.S. Pat. No. 3,688,479 to Martinson et al. discloses a leaf comminutingapparatus. The leaf comminuting apparatus is connected to a lawn mowermotor, which drives the cutting blades either by a direct connection ora belt drive. Cut blades of grass are drawn up, pulverized anddischarged from an elevated location in a lateral direction generallyperpendicular to the direction of the lawn mower motion. The leafcomminuting apparatus comprises a cylindrically shaped fan housinghaving an inlet opening and an outlet, a suction nozzle connected to theinlet opening, a fan mounted in the housing to provide suction at theinlet and a drive shaft connecting the fan to a motor. Comminutingaction is accomplished by close movement of movable blades affixed tothe outer end of the blades of a fan, which interact with fixed bladesattached to the walls the fan housing. A portion of the fan housingcarries perforations through which an air stream passes. Finely choppedlawn clippings are carried away by the air stream, while pulverizationof larger fragments is continued. Use of a suction fan to comminute andtransport the comminuted lawn clippings causes the perforations tobecome clogged. Suction is reduced and the apparatus can even stall whenthe device becomes completely plugged. Belt slippage is not infrequent.The elevated, low velocity air stream discharge results in non-uniformdistribution of the chopped clippings.

U.S. Pat. No. 3,790,094 to Spicer discloses a mobile leaf pulverizercomprising a mobile pick-up housing having wheels, an elongated bladeand a power source. A separate pulverizer is connected to the powersource through a belt drive. The housing includes an annular sidewall, atop wall having an outlet opening, and an annular lip providing a planarsurface parallel to the plane containing the elongated blade. Rotationof the blade, which carries metal vanes oriented at a 45-degree angleconstricted to operate between the housing sidewalls progressively drawsleaves from the ground upward into the housing. The leaves move from thehousng into the pulverizer where they are ground up by cutter bladestherewithin. Pulverized leaves exit the pulverizer through slots in itshousing. Leaves processed by the Spicer device are pulled up by theblade into the pick-up housing. The leaves are then forced into thepulverizer, where they are ground up using cutter blades and dischargedfrom an elevated location. This discharge does not promote uniformdistribution of the pulverized leaves. Moreover, use of a single powersource to collect, transport and pulverize the leaves, leads to slowspeed and inefficient pulverization. Disposition of the power belt drivewithin the comminuting chamber permits large non-comminuted leaves toclog the belt drive mechanism. As a result, the pulverizer stalls, andits ability to process lawn material decreases significantly.

U.S. Pat. No. 3,940,827 to Greco discloses a leaf vacuuming attachmentfor conventional rotary lawn mowers. The attachment comprises a walledpan having a periphery that conforms to the lawn mower superstructure.When attached by clips, bolts and the like, the pan is below the lawnmower. This attachment encloses the casing of the lawn mower creating avacuum by the rotation of the mower blade. A single input port isprovided at one location on the peripheral wall of the attachment.Leaves are drawn into the chamber through a flexible hose as themovement of the blade creates a vacuum in the chamber. The leaves aredischarged in the usual manner into a grass catching bag via a chamberoutlet located about 180 degrees from the input port. No provision ismade for leaf grinding; pick-up of the leaves is accomplished by use ofa flexible, manually directed hose. Leaf discharge is not finelypulverized. The collected leaves are not uniformly distributed andapplied over the lawn.

U.S. Pat. No. 4,074,869 to Johnson discloses a vacuum blower-type mobilemachine for shredding leaves and other garden debris. The machinecomprises a housing frame, a motor for driving the drive shafts, and areduced speed drive shaft geared to a high-speed horizontal main shaftusing a planocentric type gear speed reducing arrangement A firstvertical rotor having six blades is mounted on the low speed driveshaft. The rotor functions as a vacuum blower drawing debris into thehousing. A second vertical rotor having five cutting blades is mountedon the high-speed drive shaft axially aligned and closely spaced withthe first rotor. Shredding action is accomplished in three discretesteps: (i) a stationary vane is placed in close proximity with the firstrotating rotor shredding the debris as it enters the blower; (ii) closespacing between the tailing edge of first rotor and the leading edge ofthe second rotor running at substantially increased rotational speedshreds debris by relative motion between the first and second rotorblades; and (iii) the close space between the trailing edge of thesecond rotor and the leading edge of a stationary exit-plate shredsdebris as it leaves the machine. Shredded debris is collected in a bag.Changes in the driving speed of the blower vanes and shredder vanescreate a pressure difference across the unit. Gradual shredding ofdebris assures smooth flow of debris through the machine withoutclogging. This vertical rotor configuration of the first blower as wellas the second high speed rotors results in a complicated mechanicalarrangement. Gearing is required; the belt drive is located within aregion that is in close contact with debris which is being transportedat a high velocity. Such an arrangement causes the gearing machinery andthe associated belt drive to jam. No provision is made for the uniformdistribution of the shredded debris over the lawn; instead, such debrisis collected in a bag.

U.S. Pat. No. 4,117,983 to Browning discloses a leaf collector andcomminutor having a collection receptacle. The device comprises a frame,spaced wheels supporting the frame, a gasoline or other motor, a driveshaft, and a hub carrying four rotating blades. Each blade is connectedto three sets of leaf springs, which carry blade blocks with parallelside faces. The housing has three sets of locations along the peripherywhere leaf springs carry four sets of stationary shear bars withparallel faces. During operation the three blade blocks positioned onthe rotating blade slide in between the spaces between four sets ofshear bars to create the comminutor processing action. If a stone orother large debris is encountered, the leaf springs flex, allowing easypassage of the stone and other debris. Leaves and other lawn materialare drawn into the housing through a leaf pick up nozzle due to suctioncreated by rotation of the blades. Once inside the housing the leavesare shredded through the action of the blade blocks and the shear bars.All debris processed by the comminutor is collected in a collection bin.Consequently, no provision is made for the uniform distribution of theprocessed debris over a lawn. Cutting is accomplished by shear action atthe edges of rapidly rotating blocks mounted on rotating blades andedges of shear bars mounted on the periphery of the device. No means areprovided for controlling the size of the debris during comminution.Comminution created by shear between anvils does not ensure productionof uniformly sized pulverized debris. Passage of large debris such asstones and thick twigs, is facilitated by movement of leaf springs,shear bars and blade blocks away from each other.

U.S. Pat. No. 4,214,713 to Wright discloses a mobile lawn debrispulverizer that grinds up twigs and garden debris. The pulverizercomprises an internal combustion engine having a belt drive connected tothe drive shaft of a centrifugal fan, which discharges pulverized debrisinto a collection bin in a trailer. The centrifugal fan unit createsnegative pressure transporting pulverized debris from a pulverizingunit. Each of the centrifugal fan and the pulverizing unit is connectedto the same shaft. Twigs, branches, and other material are fed into theinlet of the pulverizing unit by the negative pressure of thecentrifugal fan. Pick-up is accomplished using a flexible nozzle ofsufficient length so that rocks and stones have a chance to fall down.The housing of the pulverizing unit has a diverging frusto-conical inletand a converging frusto-conical outlet, a main inlet blade opposite anentrance anvil, and a series of blades with oppositely placed anvils.These blades rotate within the cylinder and pulverize the debris. Anentrance blade also serves to break up clumps of damp leaves and otherlawn material. The twigs and branches are further shredded through theaction of the blades in conjunction with their oppositely placed anvils.Shredded debris material exits the pulverizer through the outlet intothe centrifugal fan's inlet. No provision is made for automatic pick-upof lawn debris. Pulverizing action by shear between anvils does notensure production of uniformly sized, pulverized product. The pulverizeddebris is collected in a bin, but not uniformly distributed over a lawn.

U.S. Pat. No. 4,875,630 to Carlson discloses a stationary leaf vacuumand shredder that uses a vacuum-hose to draw lawn material into theshredder for disintegration. The shredder comprises an external motor, arotating shaft, a fan to create the required vacuum for transporting thevegetable debris, a shredding chamber with multiple loose whips,preferably made of stiff metal, attached to the rotating shaft. Leavesand other lawn material are drawn through a vacuum hose into theshredding chamber by negative pressure created by the rotating fanlocated therewithin. Lightweight lawn material is pulverized by contactwith rotating loose whips, while rocks and other hard lawn material aredeflected by the rotating loose whips and are not pulverized. The fandischarges the pulverized lawn material and deflected rock and otherhard lawn material through a discharge chute. Since only the fan createssuction, all debris has to be transported by the negative fan-createdpressure. This arrangement leads to a slow, tedious process. The lawndebris is not picked-up automatically. Shredding action depends onrepeated contact between the loose whip elements and the vegetablematter, causing unpredictability and a non-uniformly sized shreddedproduct. Shredded debris is discharged through an exit nozzle using thesame fan and is not uniformly distributed over the lawn.

U.S. Pat. No. 5,020,309 to Hopkins discloses a leaf shredder attachmentdevice for a mower bagging system. The leaf shredder attachment deviceis powered by an electrical motor. It uses rigid cutters or stringelements to further shred grass and other lawn debris which, aftershredding, is collected and bagged. The device is located within thedischarge conduit of the lawn machine between the primary cutter and thebagging unit. After passing through the leaf-shredding device, the lawnmaterial is deposited into a catcher. The leaf shredder device can alsobe attached to a hand-held leaf vacuum. Leaves are forced into the leafshredder through the action of a mower cutting blade or from a vacuumcreated by a hand-held leaf vacuum. Separate electrical power isrequired to shred lawn debris. The motor powering the shredder unit istotally encompassed by the debris flow. Plugging of bearings andcritical components is not unlikely, since motors depend on air flow tocool windings and the like. No means are provided to assure that theshredded debris is uniformly sized. The shredded lawn material is storedin the bagging unit, and not uniformly distributed over the lawn.

U.S. Pat. No. 5,231,827 to Connolly et al. discloses a lawn and gardenapparatus that can be used to collect and shred debris as well aschipping branches. The apparatus comprises a wheel-supported housinghaving a substantially closed work chamber, a drive shaft connected to agasoline-powered engine and a solid disc mounted on the drive shaft. Thedisk has four downwardly extending air moving and beating blades thatcreate a negative pressure forcing leaves and other lawn materialthrough an inlet chamber into the work chamber. After being shredded,the lawn material is forced out of the work chamber through an exitopening by the air moving blades. An outlet screen prevents largermaterial from passing through the exit opening. In addition toshredding, the apparatus is capable of chipping branches. The chippedbranches are fed through a chute. A sharpened blade, found on thetrailing edge of a slotted disc, is used to perform chipping andbranching operations. All of the shredded debris is passed to acollection bag or deflected through a nozzle. Shredding action isaccomplished via rotating air-moving blades. Leaves and other materialappointed for pulverization do not circulate inside the cylindricalframe. Consequently, the small screen often becomes clogged with largenon-pulverized debris. The device has as its principle objective thecollection and bagging of shredded debris. Projection of shredded debristhrough a nozzle results in non-uniform distribution of pulverizedproduct over the lawn.

U.S. Pat. No. 5,381,970 to Bold et al. discloses a combinationchipper/shredder and vacuum unit for lawns and gardens. The apparatuscomprises a housing containing a frame on which a single motor ismounted. Enclosed within the housing is a flat plate-like disc. Aplurality of fan blades are attached to one face of the disc, and anaperture extends adjacent to a chipper blade. The disc is coupled to adrive shaft and rotates about a horizontal axis perpendicular to theunit's direction of movement. An inlet is aligned with the chipper bladeso that the bottom edge of the inlet forms an anvil against which thechipping action takes place. As the disk rotates, limbs and other lawnmaterial are manually inserted into the chipper inlet; and are reducedto small pieces through the action of the chipper blade. The material isthen forced through a plurality of apertures provided by a screen, andcollected in a bag. For shredding smaller material, a vacuum created bythe fan blades draws leaves and other lawn material into the disc,whereon it is shredded. The shredded material is then passed through agenerally cylindrical screen and collected in a bag. In this device,larger materials are manually placed into an inlet of the device, andare not automatically picked up. However, leaves and other smaller lawnmaterials are drawn into the apparatus though the action of fan bladeslocated in the disk. These smaller lawn materials are shredded by thefan action, which is inefficient since the fan does not have cuttingblades. Coarse shredded material exiting the apparatus tends to clog thescreen. No provision is made for controlling the size of shreddeddebris; and no mechanism is provided for the uniform distribution of theshredded material over a lawn.

U.S. Pat. No. 5,707,017 to Paolucci et al. discloses a combinationblower, comminuting vacuum, and wood chipper. The apparatus comprises animpeller housing having an inlet opening and an outlet opening. Animpeller is mounted on a drive shaft located within the housing. Theimpeller includes a backing plate having radially extending blades fixedto one face thereof. Each of the impeller blades has back edges, bentperpendicular to its leading face, with serrated teeth for shredding theleaves and other lawn material. The impeller, with the cooperation ofthe volute shape of the peripheral wall, forces air in from the inletopening. After traversing the housing, the air passes out through theoutlet opening. Lawn material is forced into the housing through theaction of the impeller. Once inside the housing, the lawn material iscut into pieces by the shredder before exiting the housing through theoutlet opening. Attached to the inner face of a peripheral wall of thehousing and extending radially outward from the impeller is a statorhaving serrated teeth. The stator further shreds material as it passesthrough the housing. During operation of the device, the impellerunidirectionally forces leaves and other lawn material through thehousing, where the materials are shredded by the cutter and stator. Lawnmaterial appointed for shredding does not circulate inside thecylindrical frame. Rather, shredding of the lawn debris is restricted,occurring only for that time required for passage of the debris throughthe impeller. Shredded material exits the device after being comminutedduring a restricted residence time, governed by passage through theimpeller. There exists no mechanism for preventing incompletely shreddedlawn debris from clogging up the outlet opening. Discharge of shreddedmaterial occurs through a chute, and is, optionally, collected in a bagor left on the lawn. Debris is not shredded uniformly; and no provisionexists for uniform distribution of shredded debris over the lawn.

U.S. Pat. No. 5,860,606 to Tiederman et al. discloses a chipper/shredderfor comminuting debris such as leaves branches, and other lawn material.The chipper/shredder comprises a housing having a feed chute attached tothe front side and a chipper chute secured to the rear side. The feedchute can rotate between an upright position and a lowered position. Inthe lowered position the user can rake leaves and other lawn debris intothe interior of the housing through the chute. In the upright position,the user can place branches and other materials directly into the chute.The chipper/shredder further comprises cutting elements contained withinthe housing and an engine operatively coupled to the cutting elementsfor shredding the leaves, branches and other debris that have beeninserted. All of the material must be manually fed to this device. Noprovision is made for automatic pick-up of lawn debris. Shreddedmaterial exits the device through a chipper chute. There exists nomechanism in the device that exerts quality control over the size ofcomminuted particles, so as to prevent incompletely shredded lawn debrisfrom clogging up the chipper chute.

There remains a need in the art for a garden device that producesuniformly sized pulverized dry leaves and other lawn debris especiallysuited to form humus mulch, wherein the device either collects and holdsthe pulverized debris for distribution in the garden at a later time orautomatically distributes the debris uniformly over a lawn to enhanceits appearance and improve its soil fertility through increased organicmatter content. Also needed is a garden device that is lightweight,compact, easy to maneuver, inexpensive to construct and reliable inoperation; the use of which reduces the amount of raked leaves andgrasses accumulating in landfills.

SUMMARY OF THE INVENTION

The present invention provides a lawn debris composter that islightweight, mobile, inexpensive to construct and highly reliable inoperation. When deployed over grassy areas contiguous residential andcommercial buildings, the composter automatically draws leaves, sticks,grass and other garden refuse into a comminuting chamber, pulverizes itinto small evenly sized particles, which are i) collected in a sidecollection chamber attached to the commuting chamber and discharged byopening a gate at a user selected location or ii) automaticallydistributed uniformly over the lawn. Soil fertility is enhanced by theaddition of organic matter, and the amount of raked leaves and grassesaccumulating in landfills is reduced.

Generally stated, there is provided a composter for finely pulverizinglawn debris. The composter has a central drive shaft driven by agasoline or electrical power source. Lawn debris is drawn into a suckingchamber by a fan impeller blade mounted on the central drive shaft. Thefan impeller blade initiates pulverization of the debris in the suctionchamber. One or more grinding blades are mounted for rotation on thecentral drive shaft below the fan impeller blade. The grinding bladecarries a plurality of blade elements operative to effect additionalpulverization of the initially pulverized debris. A clutch of the toothtype or sprag type is mounted on the drive shaft below the grindingblade forming a drive shaft extension and a distributing plate ismounted directly below the clutch on the drive shaft extension. Thedistributing plate mounted for rotation on the central drive shaftextension has a plurality of inclined apertures therein for dispensing ahigh velocity stream of the pulverized debris uniformly over said lawn.The clutch may be deactivated by the user by pulling on a lever so thatthe drive shaft power is no longer delivered to the distributing plateand is immediately stopped from rotation even though the fan and thegrinding blades continue to rotate. When the distributing plate is nolonger rotating, the pulverized debris is diverted to a side collectionchamber attached to the commuting chamber wherein it is collected. In asecond embodiment, the commuting chamber and the side collection chamberare isolated from each other by a slidable gate that is opened bypulling on a sheathed cable attached to a user controlled lever. Thisisolation gate is opened simultaneously with the disengagement of theclutch that stops the rotation of the distributing plate. Opening abottom discharge gate located at the bottom of the side collectionchamber discharges the collected finely pulverized debris at aconvenient user selected location. This feature is particularly usefulwhen leaves and other garden debris are collected over a black toppavement, where the distribution of pulverized debris does not provideenrichment of soil fertility and the collected pulverized debris may besuitably applied to the soil at a desired location in the garden.

More specifically, the present invention provides a motorized, mobilelawn and garden machine that picks up leaves and debris from black topdriveways, concrete driveways and the lawn, grinds them into a fineuniform powder, and re-distributes the powder uniformly into the lawn orcollects it in a side collection chamber for discharge at a userselected location. The motorized machine picks up leaves through asuction hood located at its front portion. Leaf transport isaccomplished by negative pressure. A fan having a plurality of impellerblades is connected to a motor drive and positioned within a suction andgrinding chamber. Suction created by rotation of the fan impeller bladesproduces the negative pressure. A rotating air flow generated by fanimpeller blade motion, moves downward within the suction and grindingchamber. Interaction between the entrained dry leaves and rapidlyrotating fan impeller blades creates an initial pulverizing action. Anair stream carries the initially pulverized leaves to a plurality ofrotating grinding blades mounted on the same drive shaft as andpositioned directly below the fan impeller blades. The rotating grindingblades typically consist of alternating sets of four fan blades and fourknife-edge blades designed to grind up the dried leaves as theycirculate within the chamber. The space between the fan impeller bladesand the rotating grinding blades is selected so that the leaves carriedin the air stream are caused to undergo a substantial velocityreduction. Impact between the leaves and the rotating grinding bladescreates further pulverization. Following second state pulverization, theair stream together with the pulverized leaves is propelled verticallydownwards in a rotating flow field. The downwardly directed rotating airstream is thereby brought into contact with a rotating distributingplate, located directly below the rotating grinding blade and attachedto the same drive shaft. The rotating distributing plate has uniformlysized apertures to allow the air stream carrying pulverized, uniformlysized debris to be dispensed at a high velocity. A significant increasein air stream velocity results from centrifugal forces imparted byrotation of the distributing plate, together with air stream pressure.The apertures are angled to prevent build up of debris around theiredges and to ensure smooth flow of the air stream with pulverizeddebris. Debris particles too large to pass through the apertures arereturned back to the fan impeller blades for additional pulverization.Substantial back-pressure created in the plate area where no aperturesare present, combined with negative pressure created by the fan impellerblades, redirects these larger particles back through the rotatinggrinding blades.

A clutch is provided in the drive shaft below the grinding bladesforming a central shaft extension. The clutch may one of several typesincluding ‘tooth type’ or ‘sprag type’ or ‘electromagnetic type’. Adistributing plate is mounted on the central shaft extension below theclutch. A lever can be pulled to disengage the tooth type or sprag typeclutch so that the rotary motion is not delivered to the distributingplate. A tooth type clutch is available from many suppliers for example,http://www.daytonsuperiorproducts.com/. An electromagnetic clutchdisengages when power is turned off. The clutch disengagement leverstops the rotation of the distributing plate and is conveniently locatedwithin the operator's reach and can be used at any time, particularlywhen the garden debris pulverization apparatus is not being operated ona lawn. When a distributing plate is stopped with the fan impellerblades and grinding blades continuing to rotate, a blockage is createdin the air flow path resulting in the diversion of finely pulverizedgarden debris into the side collection chamber that is attached to thecommuting chamber. The finely pulverized garden debris that is collectedin the side collection chamber is conveniently discharged by opening abottom discharge gate at a location desired by the user. In a secondembodiment, an isolation slidable gate is incorporated between thecommuting chamber and the side collection chamber. When the rotation ofthe distributing plate is stopped by disengaging the clutch, this gateis opened either manually or through a lever arrangement.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be more fully understood and further advantages willbecome apparent when reference is had to the following detaileddescription and the accompanying drawings, in which:

FIG. 1 is a schematic diagram illustrating the apparatus for pulverizingdry leaves with provisions for either collecting pulverized debriswithin a side collection chamber or uniformly distributing pulverizeddebris on the lawn or soil depending on the engagement of the clutchlocated on the drive shaft;

FIG. 2 is a schematic diagram illustrating the apparatus for pulverizingdry leaves with provisions for either collecting pulverized debriswithin a side collection chamber incorporated with an isolation gate oruniformly distributing pulverized debris on the lawn or soil dependingon the engagement of the clutch located on the drive shaft;

FIG. 3 is a schematic diagram depicting the fan impeller blade;

FIG. 4 is a schematic diagram depicting the rotating grinding blade; and

FIG. 5 is a schematic diagram representing the rotating distributingplate with inclined holes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Grass and garden debris including dry leaves are commonly raked anddisposed of in landfills. In order for the lawn or soil to absorb theorganic content of the cut grass clippings and dry leaves as humus,there are specific requirements as to particle size and uniformity ofdistribution. Large quantities of debris, when non-uniformly appliedover a lawn, choke or smother grasses and do not decompose quicklyenough to provide sufficient nutrient value.

The present invention provides a lawn and garden machine, or composter,that picks up leaves and debris from the lawn or field, grinds them intoa powder, and re-distributes the pulverized powder into the soil.

Referring to FIG. 1 of the drawings, there is illustrated schematically,a composter 10 mounted on transportation wheels 28 and is pushed byhandle 34 in the manner of a lawn mower, lime spreader or the like. Themachine has a power source comprised of a gasoline engine or electricalmotor 32 connected to a drive shaft 23. The machine picks up leavesthrough a suction hood 36 located at the front of the device. Pick-up isaccomplished by negative pressure generated from the rotation of fanimpeller blades 22. In the embodiment shown, the fan impeller comprisesfour blade elements attached to drive shaft 23. Upon rotation of the fanimpeller blades 22, suction is created within the suction and grindingchamber 20 attached to the suction hood 36. Lawn debris is drawn intothis chamber with a nearly vertical flow pattern. The lawn debris entersthe suction and grinding chamber 20, being entrained by the air streamcreated by the fan impeller blades. During movement, the air stream andentrained debris tend to follow the flow patterns shown in FIG. 1. Thefan impeller blades impact the entrained debris initiating pulverizationthereof. The comminuting or grinding chamber 20 has a side collectionchamber 15 attached to it. The drive shaft 23 includes a clutch 14 thatis located between the grinding blade 24 and the distributing plate 26.The clutch is disengaged by pulling a lever in the clutch 14 attachedthrough a sheathed cable 18 to a lever 50 mounted on the handle frame.When the clutch is disengaged the distributing plate 26 no longerrotates and the pressure builds up within the comminuting chamber 20 andthe finely pulverized debris is diverted into the side collectionchamber 15. Periodically the side collection chamber 15 is emptied bythe user by sliding the bottom discharge gate 16. This feature isparticularly useful when leaves and garden debris are collected on ablack top or concrete driveway and there is no valid reason fordistributing finely pulverized garden debris on the black top orconcrete driveway. Instead, the finely pulverized garden debris iscollected and later discharged in the garden according to a location ofthe user's choice.

Referring to FIG. 2 of the drawings, there is illustrated schematically,a second embodiment of the composter at 10 that has all the features ofFIG. 1 with an additional feature of an isolation gate 17 locatedbetween the comminuting chamber 20 and the side collection chamber 15.The gate is opened by the user by pulling a sheathed cable 19 using alever located in the frame at 60. This gate is opened when the clutch 14is disengaged to stop the distributing plate 26. The levers 50 and 60are shown separately in this figure but may be combined in the form of asingle lever with two attachments for disengaging the clutch and openingthe gate, respectively.

In FIG. 3 the construction of the fan impeller 22 is schematicallyshown. The fan impeller shown contains four blade elements pitched todrive air stream in a downward direction when the fan impeller blade isrotated in the direction shown by the arrow. Preferably, the fanimpeller blade contains from 2 to 6 blade elements, the blade numberbeing governed by design details. The blades are pitched to drive an airstream carrying the lawn debris downwards when rotated as indicated inFIG. 1. Each blade has a sharp edge 38 and a blunt edge 40, as shown inFIG. 2. The air stream flow has a rapid, circular, and rotational motionas well as a downward flow pattern and subsequently carries thepulverized leaves with a rotating vertical downward flow into aplurality of rotating grinding blades 24.

FIG. 4 illustrates the design of the rotating grinding blades 24. Eachof the grinding blades 24 consists of alternating sets of four fanblades 43 and four knife-edge blades 42 designed to grind up the driedlawn debris as it circulates in the chamber. Preferably, the rotatinggrinding blade contains from about 2 to 6 fan blades and about 2 to 6knife edge blades depending on design considerations. Each of therotating grinding blade sets is attached to the same drive shaft. Withthis arrangement, the grinding blade sets are driven at the samerotational speed as the fan impeller; but have a substantially higherpulverizing and grinding capability due to the increased number of bladeelements contained therein.

In addition, the vertical spacing between the fan impeller blades androtating grinding blades is selected so that initially pulverized debriscarried in the air stream has a sufficient time interval with which toslow down after exiting the fan impeller blades. With this arrangement,the initially pulverized debris carried by the air stream will impactthe rotating grinding blades at significantly higher impact velocities,thereby creating further pulverization. Preferably, the distance betweenthe fan impeller blades and the rotating grinding blades is about 2 to 8inches, and most preferably 4 inches. The overall airflow for theentrained pulverized leaves is generally vertically downwards androtational, since rotational movement of the air stream follows therotational direction of the fan impeller blades and the rotatinggrinding blades, as shown by the arrows in FIG. 1. The powdered leavescarried in the air stream are then forced onto the rotating distributingplate 26, which is located below the rotating grinding blades. Thisplate has a number of sized holes designed to allow leaves which areground to specific particle sizes to escape with the air streamdischarge into the lawn.

In FIG. 5 various details of the rotating distributing plate 26 areillustrated. The rotating distributing plate is attached to the driveshaft 23. Its top and bottom surfaces are shown at 44 and 48,respectively. Bottom surface 44 is preferably separated from the groundtherebeneath by a distance of about 2 to 6 inches, more preferably 4inches, to prevent impact with rocks and other hard material present onthe lawn. This clearance also provides sufficient distance for dischargeof the air stream carrying pulverized material forcefully into the lawn.Distributing plate 26 imparts centrifugal forces to the pulverizeddebris and facilitates its high velocity exit from the rotatingdistributing plate as well as its uniform distribution over the lawn.Apertures 32 in distributing plate 26 are uniquely bored at an angleranging from about 45° to 60° inclined generally radially outward in thedirection of plate rotation. That is to say, apertures 32 are inclinedin both the radial outward direction and along the direction of rotationto smoothly carry the air flow and the pulverized debris, withoutexcessive deposition of pulverized material around the edges of theapertures. In an alternate embodiment, illustrated by cross-section XXof FIG. 5, the apertures are inclined along the radial outward directionsolely. These uniformly sized apertures govern the size of thepulverized dry leaves, assuring that the reduced particles have asubstantially uniform size. Larger sized debris particles, which areinsufficiently pulverized, are returned back to the fan impeller blades.Return of these particles is facilitated by portions 33 of distributingplate 26 that do not contain apertures 32. These portions 33 tend toblock the air flow, allowing entrained particles therein to be pushedback toward the suction and grinding chamber. The vacuum suction of thefan impeller blades pulls these larger sized particles along the flowpath shown in FIG. 1, causing them to reenter the suction and grindingchamber, wherein they receive additional pulverization. High velocitydischarge of debris entrained within the air stream assuressubstantially uniform distribution of pulverized debris over the lawn orsoil without undue buildup. When the distributing plate 26 is stopped bydisengaging the clutch 14, the finely pulverized garden debris iscollected in the side collection chamber 15 and periodically dischargedby the user by opening the bottom discharge gate 16 at a suitable gardenlocation. In a second embodiment, an isolation gate is employed betweenthe grinding chamber 20 and the side collection chamber 15 at 17 so thatwhen the distributing plate 26 is stopped from rotation by disengagingthe clutch 14, the gate 17 is opened by operating the lever at 60.

Since the fan impeller blades 22, grinding blades 24 and distributingplate 26 are all connected to the same drive shaft and rotate at thesame speed, the composter requires no belts or gears which, if present,would likely become clogged by pulverized debris. An external singlepower source comprised of an electrical motor or gasoline engine powersthe drive shaft. Energy is conserved and efficiency enhanced, since nopower is lost in gear drives or belt drives subject to belt slipping.Changing the speed of the drive shaft provides different levels ofsuction and leaf pulverization, as well as the capability fordistribution of pulverized debris.

Since the suction hood is vertical and approximately the same height asthe suction and grinding chamber, the leaves have to be picked-upsubstantial distances before entering the suction chamber. Heavierobjects such as stones are not readily raised to this height by thenegative suction pressure, therefore substantially avoiding impellerblade contact with such objects. Reliability of the composter isimproved and its service life is prolonged.

Having thus described the invention in rather full detail, it will beunderstood that such detail need not be strictly adhered to, but thatadditional changes and modifications may suggest themselves to oneskilled in the art, all falling within the scope of the invention asdefined by the subjoined claims.

1. An apparatus for finely pulverizing lawn debris, comprising: a. aframe having attached thereto a suction hood, a suction and grindingchamber, a side collection chamber and a plurality of transportationwheels; b. a power source mounted on said suction and grinding chamber,and operably connected to a central drive shaft to provide power forpulverization and distribution of said lawn debris; c. a fan impellerblade mounted on said central drive shaft for drawing said lawn debristhrough said suction hood and effecting initial pulverization of saidlawn debris; d. a grinding blade mounted for rotation on said centralshaft for effecting further pulverization of said initially pulverizeddebris; e. a clutch mounted on said central shaft forming a centralshaft extension; f. a distributing plate mounted for rotation on saidcentral shaft extension, said distributing plate having a plurality ofinclined apertures therein for dispensing a high velocity stream of saidpulverized lawn debris uniformly over a lawn when said distributingplate is rotating; and g. a clutch disengagement means for stopping saidrotation of said distributing plate to enable collection of finelypulverized garden debris in said side collection chamber.
 2. Anapparatus for finely pulverizing lawn debris as recited by claim 1,wherein said power source is a gasoline powered engine.
 3. An apparatusfor finely pulverizing lawn debris as recited by claim 1, wherein saidpower source is an electrical motor.
 4. An apparatus for finelypulverizing lawn debris as recited by claim 1, wherein said fan impellerblade comprises two to six blade elements.
 5. An apparatus for finelypulverizing lawn debris as recited by claim 4, wherein said fan impellerblade comprises four blade elements.
 6. An apparatus for finelypulverizing lawn debris as recited by claim 1, wherein said grindingblade comprises two to six pairs of blade elements, each pair having onefan blade and one knife edge blade, wherein said blade elements arearranged on said shaft so that said fan blades and said knife edgeblades are alternately disposed.
 7. An apparatus for finely pulverizinglawn debris as recited by claim 6, wherein said grinding blade set hasfour pairs of blade elements.
 8. An apparatus for finely pulverizinglawn debris as recited by claim 1, wherein said grinding chamber isdirectly attached to said side collecting chamber.
 9. An apparatus forfinely pulverizing lawn debris as recited by claim 1, wherein saidgrinding chamber is attached to said side collecting chamber through anisolation gate which is opened when said distributing plate rotation isstopped by disengaging said clutch.
 10. An apparatus for finelypulverizing lawn debris as recited by claim 1, wherein said fan impellerblades are separated from said grinding blades by a distance rangingfrom about 2 to 8 inches.
 11. An apparatus for finely pulverizing lawndebris as recited by claim 10, wherein said fan impeller blades areseparated from said grinding blades by a distance of about 4 inches. 12.An apparatus for finely pulverizing lawn debris as recited by claim 1,wherein said apertures extend from a top surface to a bottom surface ofsaid plate, and are inclined at an angle ranging from about 45 to 60degrees with respect to said top surface.
 13. An apparatus for finelypulverizing of lawn debris as recited by claim 12, wherein said angle ofinclination of said apertures extends generally radially outward andalong direction of said plate rotation.
 14. An apparatus for finelypulverizing lawn debris as recited by claim 12, wherein said angle ofinclination of said apertures extends generally radially outward.
 15. Anapparatus for finely pulverizing lawn debris as recited by claim 1,wherein said distributing plate is separated from ground therebeneath bya distance of about 2 to 6 inches.
 16. An apparatus for finelypulverizing lawn debris as recited by claim 1, wherein said distributingplate is separated from ground therebeneath by a distance of 4 inches.